1. Running helps your brain grow.Don't worry — we're not talking bursting-through-your-skull growth. Running stimulates the creation of new nerve cells and blood vessels within the brain, an organ that tends to shrink as a person ages. Also, studies have shown that running may help increase the volume of the midbrain (which controls vision and hearing) and the hippocampus (which is linked to memory and learning).

2. Running helps your brain age better.In addition to preventing or reversing age-related shrinkage, running affects brain chemicals in a way that sets runners up to have healthier-than-average brains later in life. A study last year measured neural markers and cognitive function in middle-aged athletes and non-athletes, and while the cognitive function scores were the same, researchers found the athletes' brains showed greater metabolic efficiency and neural plasticity.

3. Running boosts your ability to learn and recall information.Another 2012 study found that at least moderately fit people did better on memory tests than those who were less fit (or not fit at all). This adds to earlier research that links running to a better ability to focus, to juggle multiple tasks, and to make distinctions.

4. Running conditions your brain to store more fuel.You already knew that training conditions your muscles to store more fuel, but a recent study suggests that your brain adapts in the same way. Researchers believe these larger glycogen stores in the brain may be one of the reasons running boosts cognitive function.

5. Running, especially in nature, helps keep your brain full of feel-good chemicals.Exercise promotes the release of the feel-good chemicals called endorphins. Additionally, like many antidepressant medications, running helps your brain hold on to mood-boosting neurotransmitters serotonin and norepinephrine. For best results, run in quiet, green spaces instead of on crowded streets — a study last year found people in parks experienced brain activity similar to that seen during meditation, while people on streets experienced frustration.